Method of increasing loft in a porous fiber reinforced thermoplastic sheet

Abstract

A method of fabricating a porous, fiber-reinforced thermoplastic sheet having increased lofting properties is provided. The method includes adding reinforcing fibers having an average length of about 5 mm to about 50 mm, and thermoplastic resin powder particles to an agitated aqueous foam to form a dispersed mixture, laying the dispersed mixture of reinforcing fibers and thermoplastic resin particles down onto a support structure, evacuating the water to form a web, generating a z-axis orientation of a portion of the reinforcing fibers, heating the web above the glass transition temperature of the thermoplastic resin, and pressing the web to a predetermined thickness to form a porous thermoplastic composite sheet having a void content of about 1 percent to about 95 percent.

1 . A method of fabricating a porous, fiber-reinforced thermoplastic sheet having increased lofting properties, said method comprising:
 adding reinforcing fibers having an average length of about 5 mm to about 75 mm, and thermoplastic resin powder particles to an agitated aqueous foam to form a dispersed mixture;   laying the dispersed mixture of reinforcing fibers and thermoplastic resin particles down onto a support structure;   evacuating the water to form a web;   generating a z-axis orientation of a portion of the reinforcing fibers;   heating the web above the glass transition temperature of the thermoplastic resin; and   pressing the web to a predetermined thickness to form a porous thermoplastic composite sheet having a void content of about 1 percent to about 95 percent.   
     
     
         2 . A method in accordance with  claim 1  wherein the reinforcing fibers comprise at least one of metal fibers, metalized inorganic fibers; metalized synthetic fibers, glass fibers, graphite fibers, carbon fibers, ceramic fibers, basalt fibers, inorganic fibers, aramid fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, and coir fibers. 
     
     
         3 . A method in accordance with  claim 1  wherein the thermoplastic resin comprises at least one of polyolefins, polystyrene, acrylonitrylstyrene, butadiene, polyesters, polybutyleneterachlorate, polyvinyl chloride, polyphenylene ether, polycarbonates, polyestercarbonates, acrylonitrile-butylacrylate-styrene polymers, and amorphous nylon. 
     
     
         4 . A method in accordance with  claim 1  wherein the porous thermoplastic sheet comprises from about 20 to about 80 percent by weight of the reinforcing fibers and from about 20 to about 80 percent by weight of the thermoplastic resin. 
     
     
         5 . A method in accordance with  claim 1  wherein the porous thermoplastic sheet comprises from about 35 to about 55 percent by weight of the reinforcing fibers and from about 45 to about 65 percent by weight of the thermoplastic resin. 
     
     
         6 . A method in accordance with  claim 1  further comprising adhering a skin to at least a portion of a surface of the porous thermoplastic sheet. 
     
     
         7 . A method in accordance with  claim 6  wherein the skin comprises at least one of a thermoplastic film, an elastomeric film, a metal foil, a thermosetting coating, an inorganic coating, a fiber based scrim, a non-woven fabric, and a woven fabric. 
     
     
         8 . A method in accordance with  claim 1  wherein generating a z-axis orientation comprises:
 impinging the web with a plurality of water jets arranged in a predetermined pattern; and   evacuating any excess water from the web.   
     
     
         9 . A method in accordance with  claim 1  wherein generating a z-axis orientation comprises pulling a portion of the reinforcing fibers into a z-axis orientation with a plurality of tines oscillating in the z-axis. 
     
     
         10 . A method in accordance with  claim 1  wherein generating a z-axis orientation comprises utilizing a high consistency head box during the formation of the web. 
     
     
         11 . A method in accordance with  claim 1  wherein generating a z-axis orientation comprises generating at least about 5 weight percent of the fibers in the z-axis orientation. 
     
     
         12 . A method in accordance with  claim 1  wherein generating a z-axis orientation comprises generating about 20 to about 50 weight percent of the fibers in the z-axis orientation. 
     
     
         13 . A method in accordance with  claim 1  wherein generating a z-axis orientation comprises generating at least about 50 weight percent of the fibers in the z-axis orientation. 
     
     
         14 . A porous, fiber-reinforced thermoplastic sheet having increased lofting properties comprising:
 a plurality of reinforcing fibers bonded together with a thermoplastic resin;   said reinforcing fibers having an average length of about 5 mm to about 75 mm, at least about 5 weight percent of said reinforcing fibers orientated in a z-axis orientation;   said fiber-reinforced thermoplastic composite sheet having a void content of about 1 percent to about 95 percent.   
     
     
         15 . A porous, fiber-reinforced thermoplastic sheet in accordance with  claim 14  comprising about 20 to about 50 weight percent of said reinforcing fibers in the z-axis orientation. 
     
     
         16 . A porous, fiber-reinforced thermoplastic sheet in accordance with  claim 14  comprising at least about 50 weight percent of said reinforcing fibers in the z-axis orientation. 
     
     
         17 . A porous, fiber-reinforced thermoplastic sheet in accordance with  claim 14  wherein said reinforcing fibers comprise at least one of metal fibers, metalized inorganic fibers, metalized synthetic fibers, glass fibers, graphite fibers, carbon fibers, ceramic fibers, basalt fibers, inorganic fibers, aramid fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, and coir fibers. 
     
     
         18 . A porous, fiber-reinforced thermoplastic sheet in accordance with  claim 14  wherein said thermoplastic resin comprises at least one of polyolefins, polystyrene, acrylonitrylstyrene, butadiene, polyesters, polybutyleneterachlorate, polyvinyl chloride, polyphenylene ether, polycarbonates, polyestercarbonates, acrylonitrile-butylacrylate-styrene polymers, and amorphous nylon. 
     
     
         19 . A porous, fiber-reinforced thermoplastic sheet in accordance with  claim 14  wherein said thermoplastic sheet comprises from about 20 to about 80 percent by weight of said reinforcing fibers and from about 20 to about 80 percent by weight of said thermoplastic resin. 
     
     
         20 . A porous, fiber-reinforced thermoplastic sheet in accordance with  claim 14  wherein said thermoplastic sheet comprises from about 35 to about 55 percent by weight of said reinforcing fibers and from about 45 to about 65 percent by weight of said thermoplastic resin.